Translation:The little roe deer's fawn and the horse's gray foal are friends.
A "roe deer", correct. If you're not from Europe, you might be less familiar with them. They are rather smallish, reddish deer that are common in forests around here.
Even if you are from Europe most people usually don't really know the difference between various types of deer. Similar to how most people don't really care or know about the difference between a hare and a rabbit. This is why I find the insistence on using exclusively "roe" here so weird. Unless Hungarians are uncommonly aware of this difference I'd guess most of them would just use (small) deer and rabbit when talking about hares and roes in English.